Method and device for improving selectivity of production of low-carbon olefin from methanol conversion

Abstract

The invention belongs to the technical field of low-carbon olefin preparation, and discloses a method and device for improving selectivity of production of low-carbon olefin from methanol conversion.The method comprises the following steps: cooling a regenerated catalyst from a regenerator to a temperature lower than a methanol conversion reaction temperature through a regenerant cooler, introducing the cooled regenerated catalyst into a pre-hydrocarbon pooling facility, and carrying out a pre-hydrocarbon pooling reaction with an activation medium to form a 'hydrocarbon pool' active substances; and conveying the catalyst subjected to pre-hydrocarbon pooling activation treatment into a conversion reactor to be recycled. According to the invention, the pre-hydrocarbon pooling facility is arranged; the regenerated agent is subjected to pre-hydrocarbon pooling treatment, so that the regenerant forms hydrocarbon pool active substances and carbon deposit before entering the methanol conversion reactor, and the hydrocarbon pool active substance distribution and carbon deposit distribution of the catalyst in the methanol conversion reactor are improved, thereby shortening or eliminating the reaction induction period and enhancing the activity and selectivity of the regeneration agent methanol-to-low carbon olefin reaction.

Description

technical field [0001] The invention relates to a method and a device for improving the selectivity of methanol conversion to light olefins. Background technique [0002] Light olefins, defined here as ethylene and propylene, are two important basic organic chemical raw materials. With the sustained and rapid economic development, the consumption of chemicals produced with ethylene and propylene as basic raw materials is increasing day by day, and the demand for chemicals produced from ethylene and propylene remains high. Ethylene and propylene are traditionally produced mainly through petroleum routes, but due to the limited supply and high price of petroleum resources, the cost of producing ethylene and propylene from petroleum resources continues to increase. With the shortage of petroleum resources, it is of great significance to use non-petroleum raw materials to produce methanol, and then to convert methanol to light olefins such as ethylene and propylene. [0003] I...

AI Technical Summary

Problems solved by technology

[0017] In summary, the "hydrocarbon pool" active species in industrially applied circulating fluidized bed reactors is dynamic and changing (its type and quantity are changing with reaction conditions (mainly reaction temperature)), so The catalyst bed not only has the problem of carbon deposit distribution, but also has the problem of uneven distribution of active species in the "hydrocarbon pool", which will inevitably affect the catalytic activity and selectivity of the reaction of methanol to light olefins

In fact, this is the main reason for the low yield of low-carbon olefins in the MTO unit

But for a long time, the above-mentioned problems have not been discovered by people, and no one has carried out special research and reports so far.

[0019] At the same time, the high-temperature regenerated catalyst directly enters the conversion reactor, and there is a temperature difference of hundreds of degrees (usually 150-300°C) with the catalyst in the conversion reactor, which will cause local overheating of the catalyst bed (the high-temperature regenerated agent itself and its surroundings), This leads to many side reactions in the conversion reaction process, a large amount of coke, and poor selectivity of low-carbon olefins

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